Medical device delivery system with alignment feature

ABSTRACT

A delivery system for delivering an implantable heart valve includes an outer shaft and an inner shaft that is slidingly disposable within an outer shaft lumen, the inner shaft including a distal end region. A plurality of fingers extend distally relative to the distal end region of the inner shaft and are adapted to releasably engage an implantable heart valve. A plurality of looped sheathing aids extend distally from the distal region of an inner shaft lumen and are adapted to guide the implantable heart valve back into the outer shaft lumen when the implantable heart valve is pulled back into the outer shaft lumen. Each of the plurality of looped sheathing aids include a distal petal adapted to engage tissue adjacent a native valve annulus in order to limit distal advancement of the implantable heart valve during deployment of the implantable heart valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 toU.S. Provisional Application Ser. No. 62/627,331, filed Feb. 7, 2018,the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure pertains generally to valve delivery devices andmore particularly to valve delivery devices that facilitate alignment ofthe valve to the native annulus.

BACKGROUND

Medical devices typically used for cardiovascular system treatments mayinvolve complex and invasive therapies resulting in significantdiscomfort, pain, and long recovery times for patients. Recently, lessinvasive, percutaneous treatments have been developed. There is anongoing need for improved, less invasive cardiovascular treatments.

SUMMARY

The disclosure provides design, material, and manufacturing methodalternatives for valve delivery devices, particularly valve deliverydevices that facilitate coaxial alignment of the valve with the nativeannulus. An example of the disclosure is a delivery system fordelivering an implantable heart valve. The delivery system includes anouter shaft having an outer shaft lumen extending therethrough and aninner shaft that is slidingly disposable within the outer shaft lumenand includes a distal end region, the inner shaft defining an innershaft lumen therethrough. A plurality of fingers extend distallyrelative to the distal end region of the inner shaft and are adapted toreleasably engage an implantable heart valve. A plurality of loopedsheathing aids extend distally from the distal region of the inner shaftlumen and are adapted to guide the implantable heart valve back into theouter shaft lumen when the implantable heart valve is pulled back intothe outer shaft lumen. Each of the plurality of looped sheathing aidsinclude a distal petal adapted to engage tissue adjacent a native valveannulus in order to limit distal advancement of the implantable heartvalve during deployment of the implantable heart valve.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may include a length of wire shapedinto a first leg and a second leg, with the distal petal therebetween.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may be laser cut from a piece ofmetal to include a first leg, a second leg, with the distal petaltherebetween.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may be adapted to be manuallyadjusted in shape prior to use.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may include stainless steel.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may be biased into a configuration inwhich each distal petal is positioned to engage the tissue adjacent anative valve annulus and may be further adapted to deflect away from thebiased shape for advancing the delivery system into a position in whichthe implantable heart valve is positioned proximate the native valveannulus.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may include a shape memory material.

Alternatively or additionally to any embodiment above, each of theplurality of looped sheathing aids may include a nickel titanium alloy.

Alternatively or additionally to any embodiment above, the implantableheart valve may include an implantable aortic valve, and each of theplurality of looped sheathing aids may include a distal petal adapted toengage a sinus of Valsalva adjacent a native aortic annulus.

Alternatively or additionally to any embodiment above, the deliverydevice may further include a coupler that is secured to the distal endregion and defines a coupler lumen extending therethrough in coaxialalignment with the inner shaft lumen. The plurality of fingers extenddistally from the coupler and the plurality of looped sheathing aidsextend distally from within the coupler lumen.

Alternatively or additionally to any embodiment above, the plurality offingers may be part of a tubular member forming the coupler.

Another example of the disclosure is a delivery system for delivering animplantable heart valve. The delivery system includes an outer sheaththat is adapted to reversibly house the implantable heart valve therein.An inner member is slidingly disposed within the outer sheath anddefines an inner member lumen. The inner member is adapted to releasablysecure the implantable heart valve and to advance the implantable heartvalve from a position within the outer sheath to a position distal ofthe outer sheath. Three looped sheathing aids extend distally throughthe inner member lumen, each of the three looped sheathing aidsincluding a distal petal that is adapted to engage tissue proximate anative valve annulus in order to limit distal travel of the deliverysystem. The three looped sheathing aids are adapted to guide theimplantable heart valve back into the sheath when the implantable heartvalve is pulled back into the sheath.

Alternatively or additionally to any embodiment above, the inner membermay include three fingers that extend distally from the inner member andthat may be adapted to releasably engage the implantable heart valve.

Alternatively or additionally to any embodiment above, each of the threelooped sheathing aids may be biased into a configuration in which eachdistal petal is positioned to engage the tissue adjacent a native valveannulus and may be further adapted to deflect away from the biased shapefor advancing the delivery system into a position in which theimplantable heart valve is positioned proximate the native valveannulus.

Alternatively or additionally to any embodiment above, each of the threelooped sheathing aids may include a shape memory material.

Alternatively or additionally to any embodiment above, each of the threelooped sheathing aids may include a nickel titanium alloy.

Alternatively or additionally to any embodiment above, the implantableheart valve may include an implantable aortic valve, and each of thethree looped sheathing aids may include a distal petal adapted to engagea sinus of Valsalva adjacent a native aortic annulus.

Another example of the disclosure is a delivery system for delivering animplantable aortic valve. The delivery system includes an outer sheaththat is adapted to reversibly house the implantable aortic valve thereinand an inner member that is slidingly disposed within the outer sheath.The inner member defines an inner member lumen and is adapted toreleasably secure the implantable aortic valve and to advance theimplantable aortic valve from a position within the outer sheath to aposition distal of the outer sheath. Three looped sheathing aids extenddistally through the inner member lumen, each of the three loopedsheathing aids including a distal petal that is adapted to engage asinus of Valsalva adjacent a native aortic annulus in order to limitdistal travel of the delivery system.

Alternatively or additionally to any embodiment above, the three loopedsheathing aids may be further adapted to guide the implantable heartvalve back into the sheath when the implantable aortic valve is pulledback into the sheath.

Alternatively or additionally to any embodiment above, each of the threelooped sheathing aids may be formed to include a first leg and a secondleg with the distal petal disposed therebetween.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present invention.The Figures, and Detailed Description, which follow, more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is side view of an example medical device system;

FIG. 2 is a cross-sectional side view of an example outer sheath;

FIG. 3 is a transverse cross-sectional view taken through line 3-3 inFIG. 2;

FIG. 4 is a perspective view of an example inner catheter;

FIG. 5 is a cross-sectional view taken through line 5-5 in FIG. 4;

FIG. 6 is a cross-sectional view taken through line 6-6 in FIG. 4;

FIG. 7 is a perspective view of a portion of an example implantassociated with the example medical device system;

FIG. 8 through FIG. 11 are perspective views that illustrate an examplemechanism for locking an implant;

FIG. 12 is a side view of a delivery system including a plurality oflooped sheathing aids;

FIG. 13 is a side view of the delivery system of FIG. 12, shown with asheath partially advanced over the plurality of looped sheathing aids;

FIG. 14 is a side view of the delivery system of FIG. 12, shown with thesheath more fully advanced over the plurality of looped sheathing aids;

FIG. 15 is a schematic top view of a native aortic valve annulus;

FIG. 16 is a perspective view of an example inner catheter; and

FIG. 17 is a perspective view of a portion of an example implantassociated with the example medical device system.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the disclosureto the particular embodiments described. On the contrary, the intentionis to cover all modifications, equivalents, and alternatives fallingwithin the spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may include numbers thatare rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

Diseases and/or medical conditions that impact the cardiovascular systemare prevalent in the United States and throughout the world.Traditionally, treatment of the cardiovascular system was oftenconducted by directly accessing the impacted part of the system. Forexample, treatment of a blockage in one or more of the coronary arterieswas traditionally treated using coronary artery bypass surgery. As canbe readily appreciated, such therapies are rather invasive to thepatient and require significant recovery times and/or treatments. Morerecently, less invasive therapies have been developed, for example,where a blocked coronary artery could be accessed and treated via apercutaneous catheter (e.g., angioplasty). Such therapies have gainedwide acceptance among patients and clinicians.

Some relatively common medical conditions may include or be the resultof inefficiency, ineffectiveness, or complete failure of one or more ofthe valves within the heart. For example, failure of the aortic valvecan have a serious effect on a human and could lead to serious healthcondition and/or death if not dealt with. Treatment of defective heartvalves poses other challenges in that the treatment often requires therepair or outright replacement of the defective valve. Such therapiesmay be highly invasive to the patient. Disclosed herein are medicaldevices that may be used for delivering a medical device to a portion ofthe cardiovascular system in order to diagnose, treat, and/or repair thesystem. At least some of the medical devices disclosed herein may beused to deliver and implant a replacement heart valve (e.g., areplacement aortic valve). In addition, the devices disclosed herein maydeliver the replacement heart valve percutaneously and, thus, may bemuch less invasive to the patient. The devices disclosed herein may alsoprovide a number of additional desirable features and benefits asdescribed in more detail below.

FIG. 1 is a side view of an example medical device system 10. It shouldbe noted that some features of the system 10 are either not shown, orare shown schematically, in FIG. 1 for simplicity. Additional detailsregarding some of the components of the system 10 are provided in otherfigures in greater detail. The system 10 may be used to deliver and/ordeploy a variety of medical devices to a number of locations within theanatomy. In at least some cases, the system 10 is a replacement heartvalve delivery system (e.g., a replacement aortic valve delivery system)that can be used for percutaneous delivery of a replacement heart valve.This, however, is not intended to be limiting as the system 10 may alsobe used for other interventions including mitral valve replacement,valve repair, valvuloplasty, and the like, or other similarinterventions.

The system 10 may generally be described as a catheter system thatincludes an outer sheath or catheter 12 and an inner catheter or tube 14(a portion of which is shown in FIG. 1 in phantom line) extending atleast partially through the outer sheath 12. A medical device implant 16may be coupled to the inner catheter 14 and disposed within the outersheath 12 during delivery of the implant 16. A handle 18 may be disposedat the proximal end of the outer sheath 12 and the inner catheter 14. Ingeneral, the handle 18 may be configured to manipulate the position ofthe outer sheath 12 relative to the inner catheter 14 as well as aid inthe deployment of the implant 16.

In use, the system 10 may be advanced percutaneously through thevasculature to a position adjacent to an area of interest. For example,the system 10 may be advanced through the vasculature to a positionadjacent to a defective aortic valve. During delivery, the implant 16may be generally disposed in an elongated and low profile “delivery”configuration within the outer sheath 12. Once positioned, the outersheath 12 may be retracted to expose the implant 16. The implant 16 maybe actuated in order to expand implant into a generally shortened andlarger profile “deployed” configuration suitable for implantation withinthe anatomy. When the implant 16 is suitably deployed within theanatomy, the system 10 can be removed from the vasculature, leaving theimplant 16 in place to function as, for example, a suitable replacementfor the native aortic valve. In at least some interventions, the implant16 may be deployed within the native valve (e.g., the native valve isleft in place and not excised). Alternatively, the native valve may beremoved and implant 16 may be deployed in its place as a replacement.

FIG. 2 through FIG. 11 illustrate some of the components of the system10. For example, FIG. 2 is a cross-sectional side view of the outersheath 12. Here it can be seen that the outer sheath 12 has a proximalportion 20 and a distal portion 22. The distal portion 22 may have aslightly enlarged or flared inner diameter, which may provide additionalspace for holding the implant 16 therein. For example, the innerdiameter of the outer sheath 12 along the proximal portion 20 may be inthe range of about 0.254 to 1.27 cm (0.10 to 0.50 inches), or about0.508 to 1.016 cm (0.20 to 0.40 inches), or about 0.508 to 0.762 cm(0.20 to 0.30 inches), or about 0.56388±0.0508 cm (0.222±0.002 inches).The inner diameter of the outer sheath 12 along the distal portion 22may be in the range of about 0.254 to 1.27 cm (0.10 to 0.50 inches), orabout 0.508 to 1.016 cm (0.20 to 0.40 inches), or about 0.508 to 0.762cm (0.20 to 0.30 inches), or about 0.579 to 0.5842 cm (0.228 to 0.230inches). At the distal end of the distal portion 22 may be a distal tip24, which may be flared or otherwise have a funnel-like shape. Thefunnel-like shape increases the outer diameter (and inner diameter) ofthe outer sheath 12 at the distal tip 24 and may aid in the sheathingand/or re-sheathing of the implant 16 into the outer sheath 12. Otherthan at the distal tip 24, the outer sheath 12 may have a generallyconstant outer diameter. For example, the outer sheath 12 may have anouter diameter in the range of about 0.254 to 1.27 cm (0.10 to 0.50inches), or about 0.508 to 1.016 cm (0.20 to 0.40 inches), or about0.508 to 0.762 cm (0.20 to 0.30 inches), or about 0.6858 cm (0.270inches). These are just examples. Other embodiments are contemplatedthat have differing dimensions (including those appropriate fordifferently sized patients including children) and/or arrangements forthe outer diameter and/or inner diameter of the outer sheath 12. Thesecontemplated embodiments include outer sheaths with flared or otherwisevariable outer diameters, embodiments with constant inner diameters,combinations thereof, and the like. The outer sheath 12 may also have alength that is appropriate for reaching the intended area of interestwithin the anatomy. For example, the outer sheath 12 may have a lengthin the range of about 30 to 200 cm, or about 60 to 150 cm, or about 100to 120 cm, or about 108±0.20 cm. The outer sheath 12 may also be curved.For example, a distal section of the outer sheath 12 may be curved. Inone example, the radius of the curve (measured from the center of theouter sheath 12) may be in the range of about 2 to 6 cm (20 to 60 mm),or about 3 to 4 cm (30 to 40 mm), or about 3.675 cm (36.75 mm). Again,these dimensions are examples and are not intended to be limiting.

The outer sheath 12 may be formed from a singular monolithic tube orunitary member. Alternatively, the outer sheath 12 may include aplurality of layers or portions. One or more of these layers may includea reinforcing structure such as a braid, coil, mesh, combinationsthereof, or the like. FIG. 3 is a cross-section taken along line 3-3 ofFIG. 2 illustrating one example of a multilayer structure for the outersheath 12. For example, the outer sheath 12 may include an inner lineror layer 26. An intermediate or tier layer 28 may be disposed on theinner liner 26. A reinforcement 30 may be disposed on the intermediatelayer 28. A topcoat or outer layer 32 may be disposed on thereinforcement 30. Finally, an outer coating 34 (e.g., a lubriciouscoating, a hydrophilic coating, a hydrophobic coating, etc.) may bedisposed along portions or all of the topcoat 32. These are justexamples. Several alternative structural configurations are contemplatedfor the outer sheath 12 including embodiments including two or morelayers that may be different from those shown in FIG. 3, embodimentswithout a reinforcement, and the like, or other suitable configurations.

The dimensions and materials utilized for the various layers of theouter sheath 12 may also vary. For example, the inner liner 26 mayinclude a polymeric material such as fluorinated ethylene propylene(FEP) and may have a thickness in the range of about 0.00254 to 0.0127cm (0.001 to 0.005 inches) or about 0.00762±0.00254 (0.003±0.001inches), the intermediate layer 28 may include a polymer material suchas polyether block amide (e.g., PEBAX 6333) and may have a thickness inthe range of about 0.00254 to 0.0127 cm (0.001 to 0.005 inches) or about0.00508±0.00254 (0.002±0.001 inches), the outer coating 34 may include apolymer material such as polyether block amide (e.g., PEBAX 7233) andmay have a thickness in the range of about 0.00254 to 0.0254 cm (0.001to 0.01 inches). In some embodiments, the outer coating 34 may vary inthickness. For example, along the proximal portion 20 the outer coating34 may have greater thickness, such as about 0.0127 to about 0.0508 cmor about 0.02159 cm (0.005 to 0.02 inches or about 0.0085 inches), thanalong the distal portion 22 and/or the distal tip 24, which may be about0.0127 to about 0.0508 cm or about 0.01651 cm (e.g., about 0.005 to 0.02inches or about 0.0065 inches). These are just examples as othersuitable materials may be used.

The form of the distal tip 24 may also vary. For example, in at leastsome embodiments, the inner liner 26 (i.e., a 2.5 mm section thereof)may be extended up and around the distal end of the outer sheath 12(e.g., around the reinforcement 30 and the topcoat 32). A ring member(not shown) made from a suitable material such as a 55D polyether blockamide (e.g., 55D PEBAX) may be disposed over the inner liner 26 and heatbonded to form the distal tip 24. This may form the funnel-like shape ofthe distal tip 24.

The reinforcement 30 may also vary in form. In at least someembodiments, the reinforcement 30 may take the form of a braid, coil,mesh, or the like. For example, in some embodiments, the reinforcement30 may include a metallic braid (e.g., stainless steel). In some ofthese embodiments, the reinforcement 30 may also include additionalstructures such as one or more longitudinally-extending strands. Forexample, the reinforcement 30 may include a pair oflongitudinally-extending aramid and/or para aramid strands (for example,KEVLAR®) disposed on opposite sides of the braid. These strands may ormay not be woven into portions or all of the braid.

FIG. 4 is a perspective view of the inner catheter 14. A distal endregion of the inner catheter 14 may include a step 40 in outer diameterthat defines a decreased outer diameter section 42. For example, thedecreased outer diameter section 42 may have an outer diameter in therange of about 0.127 to 0.635 cm (0.05 to 0.25 inches), or about 0.254to 0.508 cm (0.10 to 0.20 inches), or about 0.38608±0.00762 (0.152±0.003inches) as opposed to the remainder of the inner catheter 14 where theouter diameter may be in the range of about 0.127 to 0.762 cm (0.05 to0.30 inches), or about 0.254 to 0.635 cm (0.10 to 0.25 inches), or about0.508±0.0254 cm (0.20±0.01 inches). The decreased outer diameter section42 may define a region where other components of the system 10 may beattached. Some additional details regarding these components can befound herein.

In general, the inner catheter 14 may take the form of an extrudedpolymer tube. Other forms are also contemplated including other polymertubes, metallic tubes, reinforced tubes, or the like including othersuitable materials such as those disclosed herein. In some embodiments,the inner catheter 14 is a singular monolithic or unitary member. Inother embodiments, the inner catheter 14 may include a plurality ofportions or segments that are coupled together. The total length of theinner catheter may be in the range of about 60 to 150 cm, or about 80 to120 cm, or about 100 to 115 cm, or about 112±0.02 cm. Just like theouter sheath 12, the inner catheter 14 may also be curved, for exampleadjacent to the distal end thereof. In some embodiments, the innercatheter 14 may have one or more sections with a differinghardness/stiffness (e.g., differing shore durometer). For example, theinner catheter may have a proximal region 44 a and an intermediateregion 44 b. The proximal region 44 a may include a generally stiffpolymeric material such as a 72D polyether block amide (e.g., 72D PEBAX)and may have a length in the range of about 60 to 150 cm, or about 80 to120 cm, or about 100 to 115 cm, or about 109.5±0.02 cm. The intermediateregion 44 b may include a 40D polyether block amide (e.g., 40D PEBAX)and may have a length in the range of about 5 to 25 mm, or about 10 to20 mm, or about 15±0.01 mm. The decreased outer diameter section 42 mayalso differ from regions 44 a/44 b and, in some embodiments, may includea 72D polyether block amide (e.g., 72D PEBAX) and may have a length inthe range of about 0.5 to 2 cm (5 to 20 mm), or about 0.8 to 1.5 cm (8to 15 mm), or about 1±0.001 cm (10±0.01 mm). These are just examples.

The inner catheter 14 may include one or more lumens. For example, FIG.5, a cross-sectional view of the inner catheter 14 adjacent to aproximal end portion 36 taken at line 5-5 in FIG. 4, illustrates thatthe inner catheter 14 may include a first lumen 46, a second lumen 48, athird lumen 50, and a fourth lumen 52. In general, the lumens46/48/50/52 extend along the entire length of the inner catheter 14.Other embodiments are contemplated, however, where one or more of thelumens 46/48/50/52 extend along only a portion of the length of theinner catheter 14. For example, the fourth lumen 52 may stop just shortof the distal end of the inner catheter 14 and/or be filled in at itsdistal end to effectively end the fourth lumen 52 proximal of the distalend of the inner catheter 14. For example, as illustrated in FIG. 6,which is a cross-sectional view of the inner catheter 14 taken at line6-6 in FIG. 4, the fourth lumen 52 is absent.

Disposed within the first lumen 46 may be push-pull rods 84 (not shownin FIG. 5, seen in other figures including FIG. 7), which are used toexpand and/or elongate the implant 16 as explained in more detailherein. In at least some embodiments, the first lumen 46 may be linedwith a low friction liner 54 (e.g., a FEP liner). Disposed within thesecond lumen 48 may be a pin release mandrel 92 (not shown in FIG. 5,seen in other figures including FIG. 7), which is explained in moredetail herein. In at least some embodiments, the second lumen 48 may belined with a hypotube liner 56. The third lumen 50 may be a guidewirelumen and this lumen may also be lined with a hypotube liner 58.

The fourth lumen 52 may be used to house a non-stretch wire 60. The formof the non-stretch wire 60 may vary. In some embodiments, thenon-stretch wire 60 may take the form of a stainless steel braid. Thenon-stretch wire 60 may optionally include a pair oflongitudinally-extending aramid and/or para aramid strands (for example,KEVLAR®) disposed on opposite sides of the braid. In general, ratherthan being “disposed within” the fourth lumen 52, the non-stretch wire60 may be embedded within the fourth lumen 52. In addition, thenon-stretch wire 60 may extend to a position adjacent to the distal endportion 38 but not fully to the distal end of the inner catheter 14 asillustrated in FIG. 6 by the absence of the fourth lumen 52 adjacent tothe distal end of the inner catheter 14. For example, a short distalsegment of the fourth lumen 52 may be filled in with polymer materialadjacent to the distal end of the inner catheter 14.

Returning to FIG. 4, the inner catheter 14 may also include a guidewireextension tube 62 that extends distally from the distal end portion 38.A nose cone 64 is attached to the guidewire extension tube 62. The nosecone 64 generally is designed to have an atraumatic shape. The nose cone64 may also include a ridge or ledge 66 that is configured to abut thedistal tip 24 of the outer sheath 12 during delivery of the implant 16.

FIG. 7 illustrates some of the additional components of the system 10and the implant 16. For example, here it can be seen that the implant 16includes a plurality of valve leaflets 68 (e.g., bovine pericardial)which are secured to a cylindrical braid 70 at a post or commissure post72, for example at the commissure portions of the leaflets 68. In thisexample, the implant 16 includes three leaflets 68 secured to the braid70 with three posts 72. The leaflets 68 may also be secured to the baseor “distal end” of the braid 70. The posts 72, in turn, may be securedto the braid 70 (e.g., along the interior of the braid 70) with suturesor other suitable mechanisms. Positioned adjacent to (e.g.,longitudinally spaced from and aligned with) the posts 72 are aplurality of buckles 76, which may also be sutured to the braid 70(e.g., along the interior of the braid 70). In this example, one buckle76 is attached to the braid 70 adjacent to each of the three posts 72.Accordingly, the braid 70 has a total of three buckles 76 and threeposts 72 attached thereto. Other embodiments are contemplated wherefewer or more buckles 76 and posts 72 may be utilized. A seal 74 (shownin cross-section) may be disposed about the braid 70 and, as the namesuggests, may help to seal the implant 16 within a target implant siteor area of interest.

Attachment between the implant 16 and the inner catheter 14 (and/orouter sheath 12) may be effected through the use of a three fingercoupler 78. It will be appreciated that the coupler 78 is merely anexample, as other couplers may include additional components not shownwith the coupler 78. The coupler 78 may generally include a cylindricalbase (not shown) that is attached to the inner catheter 14 (e.g.,disposed about and attached to the reduced outer diameter section 42).Projecting distally from the base are three fingers that are eachconfigured to engage with the implant 16 at the posts 72 and the buckles76. A collar 80 may further assist in holding together these structures.A guide 82 may be disposed over each of the fingers and may serve tokeep the fingers of the coupler 78 associated with push-pull rods 84extending adjacent to the coupler 78. Finally, a pin release assembly 86may be a linking structure that keeps the posts 72, the buckles 76, andthe push-pull rods 84 associated with one another. The pin releaseassembly 86 includes a plurality of individual pins 88 that may bejoined together via a coiled connection 90 and held to a pin releasemandrel 92 with a ferrule 94.

During delivery, the implant 16 is secured at the distal end of theinner catheter 14 by virtue of the association of the fingers of thecoupler 78 being coupled with a projecting proximal end of the buckles76 (and being held in place with the collar 80 disposed over theconnection) and by virtue of the pins 88 securing together the push-pullrods 84 and the posts 72. When the implant 16 is advanced within theanatomy to the desired location, the outer sheath 12 may be withdrawn(e.g., moved proximally relative to the inner catheter 14) to expose theimplant 16. Then, the push-pull rods 84 can be used to expand and “lock”the implant 16 in the expanded or deployed configuration by proximallyretracting the push-pull rods 84 to pull the posts 72 into engagementwith the buckles 76. Finally, the pins 88 can be removed, therebyuncoupling the push-pull rods 84 from the posts 72, which allows theimplant 16 to be released from the system 10 and deployed in theanatomy.

FIG. 8 through FIG. 11 illustrate the locking system utilized with thesystem 10. For simplicity purposes, only one of the three fingers of thecoupler 78, only one of the three push-pull rods 84, and only one of theposts 72 of the example system 10 are shown (and the implant 16 is notshown). As seen in FIG. 8, the push-pull rod 84 extends through theguide 82 adjacent to the fingers of the coupler 78, through the collar80, through the buckle 76, and into a hollow t-shaped bar portion 96 ofthe post 72. The distal end of the push-pull rod 84 may include anopening or aperture (not shown) that can be aligned with an opening 98of the t-shaped bar portion 96. When so aligned, the pin 88 can belooped through the opening 98 and the opening of the push-pull rod 84.This secures the push-pull rod 84 to the post 72 and forms aconfiguration of these structures that can be utilized during deliveryof the implant 16. As can be appreciated, the proximal end of the post72 and the distal end of the buckle 76 are longitudinally separated and,accordingly, the implant 16 is in an elongated and generally low-profileconfiguration suitable for delivery.

When the implant 16 reaches the intended target site within the anatomy,a clinician can proximally retract the push-pull rod 84, thereby movingthe proximal ends of the posts 72 toward the distal ends of the buckles76 in order to expand the implant 16. Ultimately, the push-pull rod 84can be retracted sufficiently far enough to lock the post 72 with thebuckle 76 so as to lock implant in an expanded configuration suitablefor implantation within the anatomy. FIG. 9 illustrates the push-pullrod 84 proximally retracted. In doing so, the post 72 is brought intocontact with the buckle 76. More particularly, a raised, generallytransversely-oriented ridge 100 on the t-shaped bar portion 96 may bepulled proximally past the buckle 76 so that the post 72 is secured andheld in place by the buckle 76. At this point, it is possible to urgethe push-pull rods 84 distally to “unlock” the implant 16, therebyallowing for repositioning and/or retraction. Alternatively, if aclinician is satisfied with the positioning and/or locking of theimplant 16 (e.g., after visualization of the implant 16 via a suitableimaging technique), the pins 88 may be pulled (e.g., removed from theopenings 98 and the openings in the push-pull rods 84) to uncouple thepush-pull rods 84 from the posts 72 as shown in FIG. 10. Furtherretraction of the push-pull rods 84 causes a longitudinally-orientedridge 102 on the push-pull rods 84 to engage the collar 80 and causesthe collar 80 to slide proximally along the fingers of the coupler 78.In doing so, a forked end 104 of the fingers, which has a groove 106formed therein, is exposed and can be uncoupled from a rail 108, whichhas a projection 110 formed thereon that is configured to mate with thegroove 106, as shown in FIG. 11. Thereafter, the system 10 can beremoved from the anatomy, leaving behind the expanded and deployed theimplant 16.

In some cases, the system 10 may include sheathing aids that facilitatesheathing the implant 16 (FIG. 1) into the outer sheath 12 (FIG. 1). Insome instances, sheathing aids may also assist in the initial sheathingof the implant 16 (e.g. removing the implant 16 from a packagingcontainer such as a bottle and pulling the implant 16 into the outersheath 12) and in re-sheathing the implant 16 during repositioningand/or retraction of the implant 16 within the area of interest. In somecases, as will be discussed, sheathing aids may also be adapted orotherwise configured to aid in deploying the implant 16, such as bylimiting distal advancement of the implant 16 relative to an nativevalve annulus. FIG. 12 through FIG. 14 provide views of a system 210that includes sheathing aids that are adapted both to assist insheathing or re-sheathing the valve 16, but to also limit distaladvancement.

As seen in FIG. 12, the system 210 includes an outer member 212 and aninner member 214. In some instances, the outer member 212 may beconsidered as representing the outer sheath 12 while the inner member214 may be considered as representing the inner catheter 14, forexample. A plurality of looped sheathing aids 216 may be seen asextending distally from the inner member 214. A total of three loopedsheathing aids 216 are shown, although in some cases it is contemplatedthat the system 210 may have only one or two looped sheathing aids 216.In some cases, depending on peculiarities of a patient's anatomy, orwhat type of valve is being implanted, the system 210 may include morethan three looped sheathing aids 216.

In some cases, each of the looped sheathing aids 216 may be consideredas being fixed in place relative to the inner member 214. In someinstances, it is contemplated that at least some of the looped sheathingaids 216 may instead be moveably secured relative to the inner member214 such that the looped sheathing aids 216, or at least some thereof,may be moved distally or proximally in order to control the relativeposition of each of the looped sheathing aids 216.

In some cases, each of the looped sheathing aids 216 may be consideredas having a first leg 218, a second leg 220 and a distal petal 222 thatis disposed between the first leg 218 and the second leg 220. In somecases, each of the looped sheathing aids 216 may be formed from a wirethat is bent into the shape shown, having the first leg 218, the secondleg 220 and the intervening distal petal 222. In some cases, each of thelooped sheathing aids 216 may be formed by laser cutting the first leg218, the second leg 220 and the distal petal 222 from a piece of metal.

In some instances, at least some of the looped sheathing aids 216 may beadapted to be manually adjusted in shape prior to use. This may includemanually bending one or more of the looped sheathing aids 216, orportions thereof, to more accurately accommodate the particular featuresof an individual patient's cardiac anatomy, for example. In some cases,this may also or alternatively include changing a length of the firstleg 218 and/or the second leg 220 of at least some of the loopedsheathing aids 216. In some cases, the looped sheathing aids 216 may beformed of a stainless steel.

In some instances, at least some of the looped sheathing aids 216 may bebiased into a configuration in which each distal petal 222 is positionedto engage the tissue adjacent a native valve annulus and are furtheradapted to deflect away from the biased shape for advancing the deliverysystem into a position in which the implant 16 is positioned proximatethe native valve annulus. In some cases, at least some of the loopedsheathing aids 216 may be formed of a shape memory material. In someinstances, at least some of the looped sheathing aids 216 may be formedof a nickel titanium alloy such as NITINOL®. The biased shape, anddeflecting therefrom, may be seen, in part, in FIG. 13, in which theouter member 212 has been advanced distally, causing the loopedsheathing aids 216 to deflect inwardly relative to the biased positionshown for example in FIG. 12. In FIG. 14, the outer member 212 has beenadvanced further in a distal direction, causing the looped sheathingaids 216 to further deflect inwardly from the biased position shown inFIG. 12.

In some cases, the implant 16 may be an implantable aortic valve. FIG.15 is a schematic top view of a native aortic valve AV. This view may beconsidered as having sliced through the aorta above the aortic valve AV,looking downward at the native leaflets NL. Blood flow through theaortic valve AV comes up through the aortic valve AV, from the leftventricle. As shown in FIG. 15, the native leaflets NL are shown in aclosed position, in which no blood is permitted to flow through. It willbe appreciated that each of the native leaflets NL are positionedadjacent a corresponding sinus of Valsalva SV.

By comparing the configuration of the looped sheathing aids 216,particularly as shown in FIG. 12, with the anatomy shown in FIG. 15, itcan be seen that each of the three looped sheathing aids 216, or moreparticularly, the three distal petals 222 of the three looped sheathingaids 216, may fit into the corresponding sinus of Valsalva SV. As can beimagined, the three distal petals 222 fit into each sinus of ValsalvaSV, and are constrained against further distal movement because thethree distal petals 222 are in contact with each sinus of Valsalva SV.The three distal petals 222 are also constrained against further radialmovement by the wall of the aorta. Accordingly, by controlling the sizeand shape of the three looped sheathing aids 216, relative to theanatomy of a particular patient's aorta, the looped sheathing aids 216enable control of the depth at which the implant 16 is implantedrelative to the native valve.

In some cases, as shown in FIG. 16, the inner catheter 14 includes analternate coupler 178 previously discussed relative to FIG. 7 (e.g. 78).While the coupler 178 includes a total of three fingers 180 that aresimilar to the fingers shown in FIG. 7, the coupler 178 also includes atotal of three looped sheathing aids 216, as described with respect toFIG. 12. As discussed with respect to FIG. 7, each of the fingers 180may be configured to engage with the implant 16 at posts 72 and buckles76 (FIG. 7). As discussed, each of the looped sheathing aids 216 includethe first leg 218, the second leg 220 and the distal petal 222 disposedtherebetween. In some cases an actuation member 200 may extend distallythrough the inner catheter 14 and the elongate member 190.

In some cases, the coupler 178 includes an elongate member 190 thatextends between a distal end 192 of the inner catheter 14 to where thefingers 180 start. The elongate member 190 may be considered as having aproximal region 190 a and a distal region 190 b. The elongate member 190may, in some instances, include several windows 194 that are cut intothe elongate member 190 for aiding in bonding the elongate member 190 tothe inner catheter 14. In some cases, the coupler 178 may be laser cutfrom a single piece of metal, with the elongate member 190 and each ofthe fingers 180 all cut from that single piece of metal. In some cases,therefore, the coupler 178 may be considered as being integrally formed.Alternatively, in some cases, the fingers 180 may instead be welded orsoldered to the elongate member 190. In some cases, the flexibility ofthe elongate member 190 may aid in aligning the implant 16 with thenative annulus, for example. In some cases, this may also reduce theforces necessary to forward load the implant 16 during deployment. Insome cases, the looped sheathing aids 216 extend distally from aposition interior to the coupler 178.

In some cases, the three fingers 180 are each radially spaced about 120degrees apart from one another. Similarly, the three looped sheathingaids 216 are each radially spaced about 120 degrees apart from oneanother, and in some cases each looped sheathing aids 216 may be equallyspaced between adjacent fingers 180. In some cases, then, there is afinger 180 or a looped sheathing aids 216 radially spaced about 60degrees apart from a neighboring finger 180 or a neighboring loopedsheathing aids 216. While a total of three looped sheathing aids 216 areillustrated, it will be appreciated that in some cases there may be morethan three looped sheathing aids 216. While the three looped sheathingaids 216 are shown as being equally spaced apart, this is not requiredin all cases. In some cases, one or more of the looped sheathing aids216 may vary in length.

FIG. 17 is similar to FIG. 7, but illustrates the position of the loopedsheathing aids 216 relative to the implant 16. In this view, two loopedsheathing aids 216 are easily seen, as a third looped sheathing aid 216is positioned behind (in the illustrated orientation) the implant 16. Ascan be seen, the looped sheathing aids 216 extend distally from withinthe outer sheath 12. In some cases, the looped sheathing aids 216 mayextend from the inner catheter 14, but this is not required in allcases. The looped sheathing aids 216 extend about an exterior of theimplant 16, such that the looped sheathing aids 216 are able to helpguide the implant 16 back into the outer sheath 12 for sheathing orre-sheathing, in addition to the previous discussion regarding theutility of the looped sheathing aids 216 in guiding depth placement ofthe implant 16. In some cases, the looped sheathing aids 216, by virtueof their interaction with each corresponding sinus of Valsalva (SV),also help to center the implant 16 relative to the native valve.

The materials that can be used for the various components of the system10 (and/or other systems disclosed herein) and the various tubularmembers disclosed herein may include those commonly associated withmedical devices. For simplicity purposes, the following discussion makesreference to the outer sheath 12 and/or the inner catheter 14. However,this is not intended to limit the devices and methods described herein,as the discussion may be applied to other similar tubular members and/orcomponents of tubular members or devices disclosed herein.

The outer sheath 12 and/or the inner catheter 14 may be made from ametal, metal alloy, polymer (some examples of which are disclosedbelow), a metal-polymer composite, ceramics, combinations thereof, andthe like, or other suitable material. The coupler 178, 278 may be formedof a metal. Some examples of suitable metals and metal alloys includestainless steel, such as 304V, 304L, and 316LV stainless steel; mildsteel; nickel-titanium alloy such as linear-elastic and/or super-elasticnitinol; other nickel alloys such as nickel-chromium-molybdenum alloys(e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY®C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys,and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL®400, NICKELVAC® 400, NICORROS® 400, and the like),nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such asMP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 suchas HASTELLOY® ALLOY B2®), other nickel-chromium alloys, othernickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-ironalloys, other nickel-copper alloys, other nickel-tungsten or tungstenalloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenumalloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like);platinum enriched stainless steel; titanium; combinations thereof; andthe like; or any other suitable material.

As alluded to herein, within the family of commercially availablenickel-titanium or nitinol alloys, is a category designated “linearelastic” or “non-super-elastic” which, although may be similar inchemistry to conventional shape memory and super elastic varieties, mayexhibit distinct and useful mechanical properties. Linear elastic and/ornon-super-elastic nitinol may be distinguished from super elasticnitinol in that the linear elastic and/or non-super-elastic nitinol doesnot display a substantial “superelastic plateau” or “flag region” in itsstress/strain curve like super elastic nitinol does. Instead, in thelinear elastic and/or non-super-elastic nitinol, as recoverable strainincreases, the stress continues to increase in a substantially linear,or a somewhat, but not necessarily entirely linear relationship untilplastic deformation begins or at least in a relationship that is morelinear that the super elastic plateau and/or flag region that may beseen with super elastic nitinol. Thus, for the purposes of thisdisclosure linear elastic and/or non-super-elastic nitinol may also betermed “substantially” linear elastic and/or non-super-elastic nitinol.

In some cases, linear elastic and/or non-super-elastic nitinol may alsobe distinguishable from super elastic nitinol in that linear elasticand/or non-super-elastic nitinol may accept up to about 2-5% strainwhile remaining substantially elastic (e.g., before plasticallydeforming) whereas super elastic nitinol may accept up to about 8%strain before plastically deforming. Both of these materials can bedistinguished from other linear elastic materials such as stainlesssteel (that can also can be distinguished based on its composition),which may accept only about 0.2 to 0.44 percent strain beforeplastically deforming.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy is an alloy that does not show anymartensite/austenite phase changes that are detectable by differentialscanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA)analysis over a large temperature range. For example, in someembodiments, there may be no martensite/austenite phase changesdetectable by DSC and DMTA analysis in the range of about −60 degreesCelsius (° C.) to about 120° C. in the linear elastic and/ornon-super-elastic nickel-titanium alloy. The mechanical bendingproperties of such material may therefore be generally inert to theeffect of temperature over this very broad range of temperature. In someembodiments, the mechanical bending properties of the linear elasticand/or non-super-elastic nickel-titanium alloy at ambient or roomtemperature are substantially the same as the mechanical properties atbody temperature, for example, in that they do not display asuper-elastic plateau and/or flag region. In other words, across a broadtemperature range, the linear elastic and/or non-super-elasticnickel-titanium alloy maintains its linear elastic and/ornon-super-elastic characteristics and/or properties.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy may be in the range of about 50 to about 60 weightpercent nickel, with the remainder being essentially titanium. In someembodiments, the composition is in the range of about 54 to about 57weight percent nickel. One example of a suitable nickel-titanium alloyis FHP-NT alloy commercially available from Furukawa Techno Material Co.of Kanagawa, Japan. Some examples of nickel titanium alloys aredisclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which areincorporated herein by reference. Other suitable materials may includeULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available fromToyota). In some other embodiments, a superelastic alloy, for example asuperelastic nitinol can be used to achieve desired properties.

In at least some embodiments, portions or all of the outer sheath 12 andthe inner catheter 14 may also be doped with, made of, or otherwiseinclude a radiopaque material. Radiopaque materials are understood to bematerials capable of producing a relatively bright image on afluoroscopy screen or another imaging technique during a medicalprocedure. This relatively bright image aids the user of the system 10in determining its location. Some examples of radiopaque materials caninclude, but are not limited to, gold, platinum, palladium, tantalum,tungsten alloy, polymer material loaded with a radiopaque filler, andthe like. Additionally, other radiopaque marker bands and/or coils mayalso be incorporated into the design of the system 10 to achieve thesame result.

In some embodiments, a degree of Magnetic Resonance Imaging (MM)compatibility is imparted into the system 10. For example, the outersheath 12 and the inner catheter 14, or portions thereof, may be made ofa material that does not substantially distort the image and createsubstantial artifacts (i.e., gaps in the image). Certain ferromagneticmaterials, for example, may not be suitable because they may createartifacts in an MRI image. The outer sheath 12 and inner catheter 14, orportions thereof, may also be made from a material that the MRI machinecan image. Some materials that exhibit these characteristics include,for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003 such as ELGILOY®, PHYNOX®, and the like),nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such asMP35-N® and the like), nitinol, and the like, and others.

A sheath or covering (not shown) may be disposed over portions or all ofthe outer sheath 12 and the inner catheter 14 that may define agenerally smooth outer surface for the system 10. In other embodiments,however, such a sheath or covering may be absent from a portion of allof the system 10, such that the outer sheath 12 and the inner catheter14 may form an outer surface. The sheath may be made from a polymer orother suitable material. Some examples of suitable polymers may includepolytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE),fluorinated ethylene propylene (FEP), polyoxymethylene (POM, forexample, DELRIN® available from DuPont), polyether block ester,polyurethane (for example, Polyurethane 85A), polypropylene (PP),polyvinylchloride (PVC), polyether-ester (for example, ARNITEL®available from DSM Engineering Plastics), ether or ester basedcopolymers (for example, butylene/poly(alkylene ether) phthalate and/orother polyester elastomers such as HYTREL® available from DuPont),polyamide (for example, DURETHAN® available from Bayer or CRISTAMID®available from Elf Atochem), elastomeric polyamides, blockpolyamide/ethers, polyether block amide (PEBA, for example availableunder the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA),silicones, polyethylene (PE), Marlex high-density polyethylene, Marlexlow-density polyethylene, linear low density polyethylene (for exampleREXELL®), polyester, polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polytrimethylene terephthalate, polyethylenenaphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI),polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide(PPO), poly paraphenylene terephthalamide (for example, KEVLAR®),polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMSAmerican Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinylalcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS50A), polycarbonates, ionomers, biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like. In some embodiments the sheath can be blendedwith a liquid crystal polymer (LCP). For example, the mixture cancontain up to about 6 percent LCP.

In some embodiments, the exterior surface of the system 10 (including,for example, the exterior surface of the outer sheath 12 and the innercatheter 14) may be sandblasted, beadblasted, sodiumbicarbonate-blasted, electropolished, etc. In these as well as in someother embodiments, a coating, for example a lubricious, a hydrophilic, aprotective, or other type of coating may be applied over portions or allof the sheath, or in embodiments without a sheath over portion of theouter sheath 12 and the inner catheter 14, or other portions of thesystem 10. Alternatively, the sheath may comprise a lubricious,hydrophilic, protective, or other type of coating. Hydrophobic coatingssuch as fluoropolymers provide a dry lubricity which improves devicehandling and device exchanges. Lubricious coatings improve steerabilityand improve lesion crossing capability. Suitable lubricious polymers arewell known in the art and may include silicone and the like, hydrophilicpolymers such as high-density polyethylene (HDPE),polytetrafluoroethylene (PTFE), polyarylene oxides,polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics,algins, saccharides, caprolactones, and the like, and mixtures andcombinations thereof. Hydrophilic polymers may be blended amongthemselves or with formulated amounts of water insoluble compounds(including some polymers) to yield coatings with suitable lubricity,bonding, and solubility. Some other examples of such coatings andmaterials and methods used to create such coatings can be found in U.S.Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein byreference.

The coating and/or sheath may be formed, for example, by coating,extrusion, co-extrusion, interrupted layer co-extrusion (ILC), or fusingseveral segments end-to-end. The layer may have a uniform stiffness or agradual reduction in stiffness from the proximal end to the distal endthereof. The gradual reduction in stiffness may be continuous as by ILCor may be stepped as by fusing together separate extruded tubularsegments. The outer layer may be impregnated with a radiopaque fillermaterial to facilitate radiographic visualization. Those skilled in theart will recognize that these materials can vary widely withoutdeviating from the scope of the present invention.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of theinvention. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A delivery system for delivering an implantableheart valve, the delivery system comprising: an outer shaft having anouter shaft lumen extending therethrough; an inner shaft slidinglydisposable within the outer shaft lumen, the inner shaft including adistal end region and defining an inner shaft lumen therethrough; aplurality of fingers extending distally relative to the distal endregion of the inner shaft, the plurality of fingers adapted toreleasably engage an implantable heart valve; and a plurality of loopedsheathing aids extending distally from the distal region of the innershaft lumen and adapted to guide the implantable heart valve back intothe outer shaft lumen when the implantable heart valve is pulled backinto the outer shaft lumen; wherein each of the plurality of loopedsheathing aids includes a distal petal adapted to engage tissue adjacenta native valve annulus in order to limit distal advancement of theimplantable heart valve during deployment of the implantable heartvalve.
 2. The delivery system of claim 1, wherein each of the pluralityof looped sheathing aids comprise a length of wire shaped into a firstleg and a second leg, with the distal petal therebetween.
 3. Thedelivery system of claim 1, wherein each of the plurality of loopedsheathing aids are laser cut from a piece of metal to include a firstleg, a second leg, with the distal petal therebetween.
 4. The deliverysystem of claim 1, wherein each of the plurality of looped sheathingaids are adapted to be manually adjusted in shape prior to use.
 5. Thedelivery system of claim 4, wherein each of the plurality of loopedsheathing aids comprise stainless steel.
 6. The delivery system of claim1, wherein each of the plurality of looped sheathing aids are biasedinto a configuration in which each distal petal is positioned to engagethe tissue adjacent a native valve annulus and are further adapted todeflect away from the biased shape for advancing the delivery systeminto a position in which the implantable heart valve is positionedproximate the native valve annulus.
 7. The delivery system of claim 6,wherein each of the plurality of looped sheathing aids comprise a shapememory material.
 8. The delivery system of claim 6, wherein each of theplurality of looped sheathing aids comprise a nickel titanium alloy. 9.The delivery system of claim 1, wherein the implantable heart valvecomprises an implantable aortic valve, and each of the plurality oflooped sheathing aids comprise a distal petal adapted to engage a sinusof Valsalva adjacent a native aortic annulus.
 10. The delivery system ofclaim 1, further comprising a coupler secured to the distal end regionand defining a coupler lumen extending therethrough in coaxial alignmentwith the inner shaft lumen, where: the plurality of fingers extenddistally from the coupler; and the plurality of looped sheathing aidsextend distally from within the coupler lumen.
 11. The delivery systemof claim 10, wherein the plurality of fingers are part of a tubularmember forming the coupler.
 12. A delivery system for delivering animplantable heart valve, the delivery system comprising: an outer sheathadapted to reversibly house the implantable heart valve therein; aninner member slidingly disposed within the outer sheath and defining aninner member lumen, the inner member adapted to releasably secure theimplantable heart valve and to advance the implantable heart valve froma position within the outer sheath to a position distal of the outersheath; and three looped sheathing aids extending distally through theinner member lumen, each of the three looped sheathing aids including adistal petal that is adapted to engage tissue proximate a native valveannulus in order to limit distal travel of the delivery system; whereinthe three looped sheathing aids are adapted to guide the implantableheart valve back into the sheath when the implantable heart valve ispulled back into the sheath.
 13. The delivery system of claim 12,wherein the inner member comprises three fingers that extend distallyfrom the inner member and are adapted to releasably engage theimplantable heart valve.
 14. The delivery system of claim 12, whereineach of the three looped sheathing aids are biased into a configurationin which each distal petal is positioned to engage the tissue adjacent anative valve annulus and are further adapted to deflect away from thebiased shape for advancing the delivery system into a position in whichthe implantable heart valve is positioned proximate the native valveannulus.
 15. The delivery system of claim 12, wherein each of the threelooped sheathing aids comprise a shape memory material.
 16. The deliverysystem of claim 12, wherein each of the three looped sheathing aidscomprise a nickel titanium alloy.
 17. The delivery system of claim 12,wherein the implantable heart valve comprises an implantable aorticvalve, and each of the three looped sheathing aids comprise a distalpetal adapted to engage a sinus of Valsalva adjacent a native aorticannulus.
 18. A delivery system for delivering an implantable aorticvalve, the delivery system comprising: an outer sheath adapted toreversibly house the implantable aortic valve therein; an inner memberslidingly disposed within the outer sheath and defining an inner memberlumen, the inner member adapted to releasably secure the implantableaortic valve and to advance the implantable aortic valve from a positionwithin the outer sheath to a position distal of the outer sheath; andthree looped sheathing aids extending distally through the inner memberlumen, each of the three looped sheathing aids including a distal petalthat is adapted to engage a sinus of Valsalva adjacent a native aorticannulus in order to limit distal travel of the delivery system.
 19. Thedelivery system of claim 18, wherein the three looped sheathing aids arefurther adapted to guide the implantable heart valve back into thesheath when the implantable aortic valve is pulled back into the sheath.20. The delivery system of claim 18, wherein each of the three loopedsheathing aids are formed to include a first leg and a second leg withthe distal petal disposed therebetween.